Studies of the hydrobiology of a tropical lake in north-western Queensland. II. Seasonal changes in thermal and dissolved oxygen characteristics

1980 ◽  
Vol 31 (5) ◽  
pp. 589 ◽  
Author(s):  
CM Finlayson ◽  
TP Farrell ◽  
DJ Griffiths
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Environmental Conditions ◽  
Seasonal Changes ◽  
Thermal Stratification ◽  
Oxygen Depletion ◽  
Tropical Lake ◽  
North Western

The stratification characteristics of Lake Moondarra (24�34'S.,139�35'E.), a man-made lake in north- western Queensland, have been studied. Evidence is presented that the lake approximates the warm polymictic type in which no persistent thermal stratification ever develops. During the cooler months, thermal stratification breaks down during the night; in the warmer months, the intense rainstorms prevent the establishment of a persistently stratified water column. The shallowness of the lake relative to its surface areaand the prevailing environmental conditions ensure that extensive periods of oxygen depletion do not develop in the water column. It is concluded that a strong and prolonged period of thermal stratification, with subsequent serious effects of the availability of dissolved oxygen in the deeper layers, would only arise if, in a particular year. there were no significant rainstorms.

scholarly journals Limnological Comparisons of Threats to Aquatic Life Owing to Thermal Stratification in two Morphometrically Different Urban Shallow Lakes

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Nihar R. Samal ◽  
Pankaj K. Roy ◽  
Malabika B. Roy ◽  
Asis Mazumdar Mazumdar
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Shallow Lakes ◽  
Thermal Stratification ◽  
Oxygen Depletion ◽  
Daily Basis ◽  
Tropical Lakes ◽  
Aquatic Life ◽  
Delta Plain ◽  
The Impact

A minimum value in the Dissolved Oxygen distribution of two shallow lakes namely, Rabindra Sarobar in south Kolkata and Subhas Sarobar in East Kolkata in the Gangetic Delta plain, has been observed to develop in the Hypolimnion during the stratified period. This minimum is usually explained by the accumulation of organic matter from the overlying layer of water. The introduction of organic matter from allochthonous and autochthonous sources is also a likely contributor to the accelerated oxygen depletion within Hypolimnion. The thermal stratification, in general, which occurs in these tropical lakes, is of direct relevance in maintaining the water quality standards, particularly for higher aquatic life. The present article attempts to investigate the possible depletion of hypolimnetic oxygen depletion as a result of the impact of thermal stratification.  These investigations will be the basic guidelines for the fishermen and their livelihoods potentially depend upon the different varieties of fishing on daily basis. The massive summer fish kills in these lakes is a major devastating happenings that is reported by the fishermen and also it is well evident from our experimental observations.  The comparison of the biodiversity of these two lakes is attempted in the present investigation. Key Words: Thermal stratification, Dissolved Oxygen, Tropical Shallow Lake, Hypolimnion, biodiversity

Dependence of Lake Oxygen Depletion Rates on Maximum Oxygen Storage in a Partially Meromictic Lake in Alberta

1988 ◽  
Vol 45 (3) ◽  
pp. 571-576 ◽  
Author(s):  
Annette M. Trimbee ◽  
E. E. Prepas
Keyword(s):  
Dissolved Oxygen ◽  
Thermal Stratification ◽  
Oxygen Depletion ◽  
Meromictic Lake ◽  
Oxygen Storage ◽  
Lake Productivity ◽  
Lake Mixing ◽  
Hypolimnetic Oxygen

Areal rates of hypolimnetic oxygen depletion (AHOD) and winter oxygen depletion (AWOD) varied considerably from year to year in a partially meromictic lake (Narrow Lake) in central Alberta. AHOD ranged from 0.222 to 0.522 g O2∙m−2∙d−1 over four summers and AWOD ranged from 0.354 to 0.614 g O2∙m−2∙d−1 over three winters. AHOD was positively correlated with maximum storage of dissolved oxygen (O2) at the onset of summer thermal stratification (P < 0.05). Similarly, AWOD was higher in years when mixing was more complete and maximum O2 storage at freeze-up was higher. These results suggest that the prediction of O2 depletion rates for lakes with year-to-year variation in maximum O2 storage can be improved if maximum O2 storage after lake mixing is considered in addition to other factors known to influence O2 depletion rates such as lake productivity and morphometry.

scholarly journals Clarifying Water Column Respiration and Sedimentary Oxygen Respiration Under Oxygen Depletion Off the Changjiang Estuary and Adjacent East China Sea

2021 ◽  
Vol 7 ◽  
Author(s):  
Jun Zhou ◽  
Zhuo-Yi Zhu ◽  
Huan-Ting Hu ◽  
Gui-Ling Zhang ◽  
Qian-Qian Wang
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
East China Sea ◽  
Oxygen Depletion ◽  
Changjiang Estuary ◽  
East China ◽  
The Changjiang Estuary ◽  
China Sea ◽  
Bottom Waters ◽  
Water Column Respiration

The Changjiang Estuary and its adjacent East China Sea are among the largest coastal hypoxic sites in the world. The oxygen depletion in the near-bottom waters (e.g., meters above the seabed) off the Changjiang Estuary is caused by water column respiration (WCR) and sedimentary oxygen respiration (SOR). It is essential to quantify the contributions of WCR and SOR to total apparent oxygen utilization (AOU) to understand the occurrence of hypoxia off the Changjiang Estuary. In this work, we analyzed the δ18O and O2/Ar values of marine dissolved gas samples collected during a field investigation in July 2018. We observed that the δ18O values of dissolved oxygen in near-bottom waters ranged from 1.039 to 8.457‰ (vs. air), generally higher than those of surface waters (−5.366 to 2.336‰). For all the sub-pycnocline samples, the δ18O values were negatively related to O2 concentrations (r2 = 0.97), indicating apparent fractionation of δ18O during oxygen depletion in the water column. Based on two independent isotope fractionation models that quantified the isotopic distillation of dissolved oxygen concentration and its δ18O, the mean contributions of WCR and SOR to total near-bottom AOU were calculated as 53 and 47%, respectively. Beneath the pycnocline, the WCR contribution to the total AOU varied from 24 to 69%, and the SOR contribution varied from 31 to 76%. The pooled samples beneath both the pycnocline and upper mixed layer indicated that WCR contributions (%) to total AOU increased with increasing AOU (μmol/L), whereas SOR% – AOU had the reverse trend. We propose that the WCR% and SOR% contributions to the total AOU of the sub-pycnocline waters are dynamic, not stationary, with changes in ambient environmental factors. Under hypoxic conditions, we observed that up to 70% of the total AOU was contributed by WCR, indicating that WCR is the major oxygen consumption mechanism under hypoxia; that is, WCR plays a vital role in driving the dissolved oxygen to become hypoxic off the Changjiang Estuary.

Influence of oxygen concentration on the distribution of Mysis relicta Lovén in a eutrophic temperate lake

1987 ◽  
Vol 65 (11) ◽  
pp. 2646-2650 ◽  
Author(s):  
R. K. Sherman ◽  
D. C. Lasenby ◽  
L. Hollett
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Oxygen Concentration ◽  
Eutrophic Lake ◽  
Oxygen Depletion ◽  
Mysis Relicta ◽  
Depth Limit ◽  
Southern Ontario ◽  
Lower Depth ◽  
Stagnation Period

The lower depth limit of a Mysis population in Crystal Lake, southern Ontario, gradually moved upward through the summer stagnation period, generally following a position just above the 1.0 mg/L dissolved oxygen isopleth. Mysis held in bioassay chambers demonstrated a 16-h LC50 value of 1.0 mg dissolved oxygen/L. Avoidance chamber experiments revealed that Mysis could detect and move away from areas of low dissolved oxygen concentrations. It is suggested that Mysis, which has been used as an indicator of oligotrophic conditions, could survive in a mesotrophic or eutrophic lake that undergoes oxygen depletion in the hypolimnion by moving upward in the water column.

scholarly journals Particle Dynamics in Ushuaia Bay (Tierra del Fuego)-Potential Effect on Dissolved Oxygen Depletion

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 324 ◽  
Author(s):  
Ximena Flores Melo ◽  
Jacobo Martín ◽  
Lounes Kerdel ◽  
François Bourrin ◽  
Cristina Beatriz Colloca ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Oxygen Depletion ◽  
Potential Effect ◽  
Tierra Del Fuego ◽  
Benthic Organisms ◽  
Hydrographic Structure ◽  
Bottom Waters ◽  
Bottom Oxygen ◽  
Seasonal Stratification

This study examines the distribution and seasonal evolution of hydrographic, hydrodynamic, and nepheloid layers in Ushuaia Bay and the submerged glacial valley that connects it to the Beagle Channel. The hydrographic structure is highly seasonal, with a total mixing of the water column in winter and the appearance of a pycnocline between 50 and 70 m deep from spring to late autumn, mainly due to desalination. A counter-clockwise current sweeps the entire bay regardless of the season or phase of the tide. This current is at its maximum in the surface layer, allowing the rapid renewal of the bay’s waters, while deep currents are weak and imply a slow renewal of the valley’s waters. Turbid and oxygen-depleted structures are observed in summer in the valley. The combination of seasonal stratification, high organic matter inputs from planktonic production, oxygen consumption for remineralization, and sluggish circulation results in a decrease in near-bottom oxygen concentration in the glacial valley at the end of the stratified season, before mixing and re-oxygenation of the water column during the southern winter. The possible impact of dissolved oxygen depletion in the bottom waters of the valley on benthic organisms, like crustaceans, is discussed.

Diurnal and Seasonal Changes in Distribution of Two Planktonic Ostracods, Conchoecia elegans and Conchoecia alata minor

1965 ◽  
Vol 22 (3) ◽  
pp. 823-840 ◽  
Author(s):  
R. A. McHardy ◽  
B. McK. Bary
Keyword(s):  
British Columbia ◽  
Dissolved Oxygen ◽  
Water Column ◽  
Oxygen Concentration ◽  
Seasonal Changes ◽  
Temperature Limit ◽  
Time Of Day ◽  
C Elegans ◽  
Vertical Distributions ◽  
Subsurface Light

Diurnal and seasonal changes in the distributions of two planktonic ostracods, Conchoecia elegans Sars and C. alata minor McHardy, have been considered in relation to changes in the temperature, salinity, oxygen concentration, and subsurface light in Indian Arm, British Columbia. Both species occurred frequently throughout the water column except near the surface. There is the suggestion (reinforced by data from other B.C. inlets) of an upper temperature limit for C. alata minor, which is lower than for C. elegans. Salinity and dissolved oxygen environments appear to have been similar for the two species. An upinlet displacement of both species-populations which took place in the early months of the year could possibly have been initiated by water which had intruded into the depths of Indian Arm. The vertical distributions of the two species showed statistically significant changes which varied with time of day, season, and geographic position. It was not possible to show that the depth of daylight distribution was strongly related to the penetration of light.

Investigation of the Contribution of Natural Organic Runoff to Dissolved Oxygen Depletion in the Red Deer River

1979 ◽  
Vol 14 (1) ◽  
pp. 71-88
Author(s):  
S.E. Penttinen ◽  
P.H. Bouthillier ◽  
S.E. Hrudey
Keyword(s):  
Dissolved Oxygen ◽  
Red Deer ◽  
Stream Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Experimental Program ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Tributary Stream ◽  
Small Tributary

Abstract Studies on the chronic low dissolved oxygen problems encountered under winter ice in the Red Deer River have generally been unable to account for dissolved oxygen depletion in terms of known manmade inputs. An experimental program was developed to assess the possible nature and approximate bounds of oxygen demand due to natural organic runoff carried to the Red Deer River by a small tributary stream, the Blindman River. The study employed an electrolytic respirometer on stream water samples subjected to prior concentration by vacuum evaporation. Evaluation of carbon and nitrogen budgets in conjunction with the measured oxygen demand indicate that biochemical oxygen demand is originating with natural organic runoff in tributaries of the Red Deer River. The results provide a basis for estimation of the possible contribution to the observed oxygen demand in the Red Deer River originating from natural organic runoff.

Maintaining the Camps

2018 ◽  
Author(s):  
Connie Y. Chiang
Keyword(s):  
Environmental Conditions ◽  
Seasonal Changes ◽  
Natural World ◽  
Japanese American ◽  
Alkaline Soil ◽  
Water Pipelines ◽  
American Labor

This chapter focuses on the maintenance of the camps. It explores how wartime shortages and Japanese American labor protests intersected with harsh environmental conditions, complicating the WRA’s efforts to keep the camps running smoothly. One of the first challenges was finding adequate coal to heat the camps during the winter. The WRA then confronted the protests of detainees, who called attention to how seasonal changes added to their labor duties. Alkaline soil, moreover, ate away at water pipelines and required constant repairs. The natural world helped to shape modes of Japanese American resistance, as some individuals refused to work or went on strike.

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